Stromberg Choke Issue

[TR4]

I have posted this issue before but I have yet to resolve it. My Stromberg carbs were recently professionally rebuilt. When I first put them back on, the motor fired right up using the choke. The rpm's were as they should be and when the motor warmed up, I pushed the choke in and it settled down to about 850 rpm so I was excited. There was one problem though, the one carb was leaking at the choke spindle so I called the guy who rebuilt the carbs and he suggested I reset the floats so I did that and the leak seemed to go away. Now, after the car sits a while and I pull out the choke, the car will start but sputters and stumbles until I push the choke back in. It will then continue to sputter and stumble until it warms up and then it runs just fine. I tried to pull out the choke when the engine was warm and it started to sputter and will even quit if I leave the choke pulled out. I sure would appreciate any advice on what to try to get the choke working properly again.

 

[TR3driver]

That actually seems pretty close to normal, to me. It should take only partial choke to start in all but the coldest weather, then you should have to start backing off on the choke within a few seconds of getting the engine started.

Have you checked that the chokes are synchronized? That would explain the rough running until it warms up (where you would normally use only part choke).

You may need to touch up the mixture adjustment after resetting the float level.

Also, what are you using for dashpot oil?

 

[TR4]

Both chokes are connected so both are operating. Not sure if that means they are synchronized?

I believe my mixture settings are good. I did readjust them after resetting the floats. The plugs read toasty brown after I made a 50 mile run. I also did synchronize the air flow so that should be OK.

I am using the Roadster Factory Dashpot Oil. Should I try another weight oil there? I used to use a standard 20wt oil before the rebuild.

My issue is pretty bad and I fear I will not be able to get the motor started and running long enough to warm it up. It almost wants to die even though I try to pull out the choke and push it in to keep it from dying.

 

[Geo Hahn]

The Strombergs carbs' choke is quite different from the SUs (the jets are not involved) and I am not as familiar with it as I should be (considering I've been driving one for 10 years) as I have not had a need to delve into them, but...

The 'starter bar' appears to me to be a real choke inasmuch as it interferes with the air intake when rotated. I haven't sync'ed them but looks like a peek into the throats of the carbs (air cleaners off) would assure they are both in the 'clear position' when the choke is off and are rotating similarly when the choke is on.

The other half of the equation is the cam that causes the throttle disc/butterfly to open slightly when the choke is on. This has an adjustment screw that should be (I think) just shy of making contact with the cam when the choke is off and then moving the throttle shaft as soon as the choke is applied (and the cam rotated).

That description may be so basic that you already know all that and have it set -- but really it is a pretty simple set-up which is probably why you find it frustrating.

The other thing you might try (if you have an IR thermometer) is to take the temperature of the front and rear sections of the exhaust manifold right after start-up and as the engine warms. The temps should be close... if one end or the other takes longer to heat up that may narrow the issue down to one carb.

BTW, I don't think the weight of the oil in the dampers would have much effect on the starting issue -- that is somewhat important but mainly as it affects acceleration.

<span style="font-style: italic">[Ooh, I hope I got my 'affect' and 'effect' straight... my High School English teacher may be out there somewhere keeping an eye on me]</span>